/* Kid-scale type, buttons and the shared palette. No web fonts: system stack only. */
:root {
  --ink: #1d2433;
  --muted: #5b6475;
  --paper: #ffffff;
  --bg: #f3f5f9;
  --line: #d5dae3;
  --accent: #2456c9;
  --accent-ink: #ffffff;
  --correct: #1a7f37;
  --correct-bg: #e3f5e8;
  --wrong: #c62828;
  --wrong-bg: #fdeaea;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 20px;
  line-height: 1.4;
  -webkit-text-size-adjust: 100%;
}

h1 {
  font-size: 1.6em;
  line-height: 1.2;
  margin: 0 0 0.4em;
}

h2 {
  font-size: 1.1em;
  margin: 0 0 0.4em;
}

a {
  color: var(--accent);
}

.page {
  max-width: 880px;
  margin: 0 auto;
  padding: 24px 16px 48px;
}

.card {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 24px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 56px;
  min-width: 48px;
  padding: 0 24px;
  border: 2px solid var(--line);
  border-radius: 14px;
  background: var(--paper);
  color: var(--ink);
  font: inherit;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  touch-action: manipulation;
}

.btn:hover {
  border-color: var(--accent);
}

.btn:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 2px;
}

.btn[aria-pressed="true"] {
  border-color: var(--accent);
  background: #e8eefc;
}

.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--accent-ink);
}

.btn-small {
  min-height: 48px;
  padding: 0 16px;
  font-size: 0.85em;
}

.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.muted {
  color: var(--muted);
}

[hidden] {
  display: none !important;
}